Much attention has recently been devoted to producing flame retardant foam plastics since these materials have found their way into widespread use in homes, offices, autos, etc. where the reduction of fire hazard is an important objective. An objective of almost equal importance is to reduce the amount of smoke produced when foam materials burn since a very serious threat to personal safety is posed by the effects of smoke in obscuring the vision of and asphyxiating persons exposed to the smoke.
Various chemical additives have been incorporated in such foams in an effort to reduce smoke. In particular, certain aliphatic acids, such as fumaric acid, have been shown to reduce smoke in certain polymer foams, such as polyisocyanurates and polyurethanes. However, the compounds of this invention are much more efficient smoke reductants in similar foam formulations at the same acid-equivalent concentration even though their empirical formulas are the same or very similar to the aliphatic acids.